The development of improved liquid crystal ("LC") flat-panel displays is an area of very active research, driven in large part by the proliferation of and demand for portable electronic appliances, including computers and wireless telecommunications devices. Moreover, as the quality of LC displays improves, and the cost of manufacturing declines, it is projected that LC displays ("LCD"s) may eventually displace conventional display technologies, such as cathode-ray-tubes.
One aspect of LCDs, to which significant research has been directed in recent years, is the demand for such displays to provide full-color images. It is quite possible that LCDs capable of displaying full-color images, at full-motion video rates, will eventually displace conventional cathode-ray tubes in television and computer display applications. Several characteristics of conventional LCD materials and methods of manufacturing such displays, however, present barriers to an efficient method of manufacturing full-color displays and/or reduce the display quality of full-color LCDs manufactured using conventional materials and techniques.
LCDs are constructed by trapping a thin film of LC between two substrates of glass or transparent plastic. The conventional method of trapping the LC between the substrates is to first join the substrates and then introduce a LC into the interstitial region(s) formed therebetween. The substrates are usually manufactured with transparent electrodes, typically made of indium tin oxide ("ITO"), to which electrical "driving" signals are coupled. The driving signals induce an electric field which can cause a phase change or state change in the LC material; the LC exhibiting different light-reflecting characteristics according to its phase and/or state.
The practical difficulty of manufacturing full-color displays, using conventional techniques, is controlling the reflectance wavelength maxima for each individual microscopic pixel (or sub-pixel). Conventional manufacturing techniques introduce a LC and a predetermined amount of twist agent, as a homogenous solution, into the region between the display substrates, which results in a LCD capable of displaying only one color that is dependent on the relative ratio of twist agent to LC. To realize a full-color display, a color filter having, for example, red, green and blue ("RGB") regions (corresponding to individual sub-pixels) must be used. The use of a color filter, however, reduces the overall brightness, and contrast ratio, of the display.
Therefore, what is needed in the art is a LCD, and one or more methods of manufacture thereof, that is optimized for mass production and adaptable to allow multi-color LCDs to be produced without the need for a separate color filter.